• Abstract
• How to insert extra contents
• Insert extra contents to all tabs automatically
• Updating specific property of extra contents dynamically
• Focusing to an extra contents dynamically
• Styling extra contents
• Styling with CSS Shadow Parts
• Styling with <style> element
• Styling with custom user styles
• Handle events on extra contents
• Provide drag data
• Simple case: just single drag data
• Complex case: different drag data for each action
• Override context menu
• How to clear extra contents
• Clear all extra contents from all places